A memorandum released just before midnight by the White House Office of Management and Budget states:
"We do not have a clear indication that Congress will act in time for the President to sign a Continuing Resolution before the end of the day tomorrow, October 1, 2013. Therefore, agencies should now execute plans for an orderly shutdown due to the absence of appropriations."
This announcement comes at the end of a House-Senate conference aimed to try and settle on a final agreement before the looming Monday night deadline.
Earlier this evening, the Senate voted 54-46 to reject the House-passed measure that would keep the government open while delaying Obamacare for one year.
Prior to that vote, the Republican-led House approved a third effort on the funding bill, voting 228-201 on Monday evening.